I'd be happy to.
QAnon is a conspiracy theory fueled by closed message board groups that claim to work at high levels of government. The crux of it is that all heads of State and major politicians the world over are embroiled in a child trafficking system explicitly designed to honeypot these statesmen into deep blackmail, enabling global control of world events. Like all good conspiracy theories, it is cleverly disguised as something that one might imagine could be true, but the whole thing spirals beyond reason with no shred of evidence. Some of the incidents that grabbed headlines include the Pizzagate incident where a QAnon believer went as far as shooting up a pizza restaurant claimed to be a part of the child trafficking, the theory that Ruth Bader Ginsburg is dead and her presence fabricated Weekend-At-Bernie style, and - like it or not - the Ukraine phone call that Trump made in the first place was entirely centered around Crowdstrike, which is a QAnon theory that has been disproven that Trump believed. I'm aware of your feelings on the Impeachment Fiasco, but the bottom line is that it all started when Trump read a QAnon theory on the Internet and decided he was going to run with it.
With regards to Purgeboy: if you see an account posting that is less than three days old, and recycles a lot of poorly made memes that you remember seeing already, odds are good that it may be Purgeboy. He reveals himself almost right away in the comments section: making threats about what the maga will do to lefty, moo slimes, the filth, Mexicans - anything where you get the feeling that he's trying a bit too hard to come across as racist and deranged, that's him. He also has a tell-tale distinctly unique way of spelling "phk" instead of "f**k". Once you successfully spot a few of his accounts, you really get a feel for his spam style.